Re-enable stack depth checks under ASan

[bnoordhuis]

Add a fudge factor to the stack size calculation because stack frames are bigger when running under AddressSanitizer.

[bnoordhuis]

Some of the failing test262 tests look like regular expressions with lots of backtracking. Probably needs tweaks to libregexp.c. I'll look at that later today.

test262/test/built-ins/RegExp/S15.10.2.8_A3_T15.js:28: unexpected error: SyntaxError: stack overflow
test262/test/built-ins/RegExp/S15.10.2.8_A3_T15.js:28: strict mode: unexpected error: SyntaxError: stack overflow
test262/test/built-ins/RegExp/S15.10.2.8_A3_T16.js:28: unexpected error: SyntaxError: stack overflow
test262/test/built-ins/RegExp/S15.10.2.8_A3_T16.js:28: strict mode: unexpected error: SyntaxError: stack overflow
test262/test/language/identifiers/start-unicode-10.0.0-class-escaped.js:18: unexpected error: InternalError: stack overflow
test262/test/language/identifiers/start-unicode-10.0.0-class-escaped.js:18: strict mode: unexpected error: InternalError: stack overflow
test262/test/language/identifiers/start-unicode-10.0.0-class.js:15: unexpected error: InternalError: stack overflow
test262/test/language/identifiers/start-unicode-10.0.0-class.js:15: strict mode: unexpected error: InternalError: stack overflow
test262/test/language/statements/function/S13.2.1_A1_T1.js:30: unexpected error: SyntaxError: stack overflow
test262/test/language/statements/function/S13.2.1_A1_T1.js:30: strict mode: unexpected error: SyntaxError: stack overflow

[bnoordhuis]

ASAN weirdness: new RegExp("(".repeat(152) + "x" + ")".repeat(152)) in a release build triggers the stack overflow error; debug builds don't... they can go all the way up to the max of 255 capture groups.