[android-webview] Skip signal handler registration on x86/64
[android-webview] Skip signal handler registration on x86/64

An intricate entangling of libsigchain, sigaction() chaining and
user-space SIGSEGV handling by binary translator cause persistent
crashes when a SIGSEGV handler is installed by a x86 library on
a hybrid application which uses both Arm and x86 libraries.
Backing out the crash handler as a temporary workaround.
More context in the related bug.

BUG=477444

Review URL: https://codereview.chromium.org/1059543003

Cr-Commit-Position: refs/heads/master@{#325441}
(cherry picked from commit c62077fbce7d6b2bdaa78b809498b740a3ae90f7)

TBR=primiano@chromium.org

Review URL: https://codereview.chromium.org/1090083002

(cherry picked from commit 023395bc4bde5a15980f26072a3312ac6d5243d1)

Cr-Original-Commit-Position: c805d8fce37cb1d1ff0af3dbc2c28f44a63eef52@{#485}
Cr-Original-Branched-From: 40a5878bf7670fe657f397a3825855addbaf66f7@{#317474}
Cr-Commit-Position: fe94940391158563b8e4cf7888f93321f554af93@{#122}
Cr-Branched-From: 9fdd9ec11ee753dedeffe15e7e822b13445dc287@{#323860}

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