Insert missing sampler cases in TType::buildMangledName.
Insert missing sampler cases in TType::buildMangledName.

We were missing the cases for 2D Rect samplers and external OES
samplers. This was causing an assert in the WebGL CTS in Debug.

BUG=angle:550

Change-Id: Ieefeef6ff0f9a486bf7667c7efc60dee766f03ef
Reviewed-on: https://chromium-review.googlesource.com/194122
Reviewed-by: Geoff Lang <b6fc25fe0362055230985c05cbfa8adb741ccc0f@chromium.org>
Reviewed-by: Shannon Woods <0f3694938fd5703bd548127ee497e4d604509bef@chromium.org>
Tested-by: Jamie Madill <7e492b4f1c8458024932de3ba475cbf015424c30@chromium.org>

geekboxzone/lollipop_external_chromium_org_third_party_angle,xin3liang/platform_external_chromium_org_third_party_angle,mrobinson/rust-angle,csa7mdm/angle,nandhanurrevanth/angle,ecoal95/angle,crezefire/angle,nandhanurrevanth/angle,ghostoy/angle,bsergean/angle,geekboxzone/lollipop_external_chromium_org_third_party_angle,larsbergstrom/angle,mlfarrell/angle,crezefire/angle,ppy/angle,csa7mdm/angle,crezefire/angle,xin3liang/platform_external_chromium_org_third_party_angle,android-ia/platform_external_chromium_org_third_party_angle,android-ia/platform_external_chromium_org_third_party_angle,MIPS/external-chromium_org-third_party-angle,mlfarrell/angle,MIPS/external-chromium_org-third_party-angle,vvuk/angle,mlfarrell/angle,bsergean/angle,nandhanurrevanth/angle,mybios/angle,crezefire/angle,MSOpenTech/angle,xin3liang/platform_external_chromium_org_third_party_angle,ecoal95/angle,jgcaaprom/android_external_chromium_org_third_party_angle,MSOpenTech/angle,larsbergstrom/angle,mrobinson/rust-angle,android-ia/platform_external_chromium_org_third_party_angle,android-ia/platform_external_chromium_org_third_party_angle,ghostoy/angle,mlfarrell/angle,csa7mdm/angle,larsbergstrom/angle,mybios/angle,mrobinson/rust-angle,vvuk/angle,geekboxzone/lollipop_external_chromium_org_third_party_angle,MIPS/external-chromium_org-third_party-angle,jgcaaprom/android_external_chromium_org_third_party_angle,ppy/angle,ghostoy/angle,nandhanurrevanth/angle,domokit/waterfall,vvuk/angle,ecoal95/angle,mikolalysenko/angle,jgcaaprom/android_external_chromium_org_third_party_angle,ghostoy/angle,csa7mdm/angle,mybios/angle,jgcaaprom/android_external_chromium_org_third_party_angle,geekboxzone/lollipop_external_chromium_org_third_party_angle,xin3liang/platform_external_chromium_org_third_party_angle,mrobinson/rust-angle,mybios/angle,ppy/angle,ecoal95/angle,ecoal95/angle,mikolalysenko/angle,domokit/waterfall,MSOpenTech/angle,ppy/angle,bsergean/angle,mrobinson/rust-angle,mikolalysenko/angle,MIPS/external-chromium_org-third_party-angle,vvuk/angle,bsergean/angle,MSOpenTech/angle,mikolalysenko/angle,larsbergstrom/angle