Reform tests for RegExp patterns

[leobalter]

This issue is particularly different from #705.

We currently maintain tests for RegExp patterns in test/built-ins/RegExp/S15.10*.js. I believe they belong to the language folder, probably a dedicated folder for patterns (maybe individual folders for each one).

Running a pet project I noticed NodeJS is crashing on some of these tests. I'm guessing it's due to high use of memory. While this is not an exclusive problem of test262, some of these tests could be updated/rewritten with a better assertions and better loops as the high memory/processing usage is not necessary.

Some of the files I found problems:

test/built-ins/RegExp/S15.10.1_A1_T13.js
test/built-ins/RegExp/S15.10.2.10_A5.1_T1.js
test/built-ins/RegExp/S15.10.2.11_A1_T9.js
test/built-ins/RegExp/S15.10.2.12_A1_T3.js
test/built-ins/RegExp/S15.10.2.12_A2_T3.js
test/built-ins/RegExp/S15.10.2.12_A2_T5.js
test/built-ins/RegExp/S15.10.2.12_A3_T1.js
test/built-ins/RegExp/S15.10.2.12_A3_T2.js

They are not the only thing crashing Node in that folder, but I stopped checking for each one I could solve with better loops (I've done an initial experimental work to replace these tests).

I observed NodeJS crashing using both test262-harness and the deprecated python runner.