Revert "Integrate the Irregexp Regular Expression Engine."

tests/co19/co19-runtime.status

Index: tests/co19/co19-runtime.status
diff --git a/tests/co19/co19-runtime.status b/tests/co19/co19-runtime.status
index 6aebbb470747be315a2a0fcc98eafaea4e7a0690..ca3ee3c460960995821de4da35197c7b11821e22 100644
--- a/tests/co19/co19-runtime.status
+++ b/tests/co19/co19-runtime.status
@@ -5,12 +5,17 @@
 
 [ $compiler == none && ($runtime == vm || $runtime == dartium || $runtime == ContentShellOnAndroid) ]
 
+LibTest/core/RegExp/Pattern_semantics/firstMatch_Term_A03_t01: Fail # Issue 12508
+LibTest/core/RegExp/Pattern_semantics/firstMatch_Atom_A02_t01: Fail # Issue 12508
 LibTest/core/RegExp/Pattern_semantics/firstMatch_DecimalEscape_A01_t02: Fail # Issue 12508
+LibTest/core/RegExp/Pattern_semantics/firstMatch_CharacterClassEscape_A03_t01: Fail # Issue 12508
 LibTest/core/RegExp/Pattern_semantics/firstMatch_NonEmptyClassRanges_A01_t01: Fail # Issue 12508
 LibTest/core/RegExp/Pattern_semantics/firstMatch_CharacterEscape_A06_t02: Fail # Issue 12508
 LibTest/core/RegExp/Pattern_semantics/firstMatch_NonEmptyClassRanges_A01_t05: Fail # Issue 12508
 LibTest/core/RegExp/Pattern_semantics/firstMatch_NonEmptyClassRanges_A01_t06: Fail # Issue 12508
+LibTest/core/RegExp/Pattern_semantics/firstMatch_Term_A04_t01: RuntimeError # Issue 12508
 
+LibTest/core/Match/operator_subscript_A01_t01: Fail # Issue 12508
 LibTest/core/RegExp/firstMatch_A01_t01: Fail # Issue 12508
 LibTest/core/int/toRadixString_A01_t01: Fail # co19 issue 492
 
@@ -32,6 +37,7 @@ LibTest/isolate/Isolate/spawnUri_A02_t03: Skip # Dart issue 15974
 LibTest/isolate/Isolate/spawnUri_A02_t04: Skip # Dart issue 15974
 LibTest/isolate/Isolate/spawn_A02_t02: RuntimeError # Dart issue 15617
 
+LibTest/core/RegExp/Pattern_semantics/splitQueryString_A02_t01: RuntimeError # Issue 12508
 LibTest/core/Symbol/Symbol_A01_t03: RuntimeError # Issue 13596
 LibTest/core/Symbol/Symbol_A01_t05: RuntimeError # Issue 13596