Rollup merge of #41673 - bitshifter:repr-align-codegen-test, r=arielb1
Rollup merge of #41673 - bitshifter:repr-align-codegen-test, r=arielb1

Add simple `[repr(align)]` codegen test.

Checks alloca and memcpy are aligned correctly.

Test added to as additional check for #33626.

aidancully/rust,aidancully/rust,graydon/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust,aidancully/rust,GBGamer/rust,aidancully/rust,graydon/rust,graydon/rust,GBGamer/rust,GBGamer/rust,GBGamer/rust