Remove Emscripten support

test/CodeGen/emscripten-arguments.c

-// RUN: %clang_cc1 -triple asmjs-unknown-emscripten %s -emit-llvm -o - | FileCheck %s
-
-// Basic argument/attribute tests for asmjs/Emscripten
-
-// CHECK: define void @f0(i32 %i, i32 %j, i64 %k, double %l, double %m)
-void f0(int i, long j, long long k, double l, long double m) {}
-
-typedef struct {
-  int aa;
-  int bb;
-} s1;
-// Structs should be passed byval and not split up.
-// CHECK: define void @f1(%struct.s1* byval align 4 %i)
-void f1(s1 i) {}
-
-typedef struct {
-  int cc;
-} s2;
-// Single-element structs should be returned as the one element.
-// CHECK: define i32 @f2()
-s2 f2() {
-  s2 foo;
-  return foo;
-}
-
-typedef struct {
-  int cc;
-  int dd;
-} s3;
-// Structs should be returned sret and not simplified by the frontend.
-// CHECK: define void @f3(%struct.s3* noalias sret %agg.result)
-s3 f3() {
-  s3 foo;
-  return foo;
-}
-
-// CHECK: define void @f4(i64 %i)
-void f4(long long i) {}
-
-// i8/i16 should be signext, i32 and higher should not.
-// CHECK: define void @f5(i8 signext %a, i16 signext %b)
-void f5(char a, short b) {}
-
-// CHECK: define void @f6(i8 zeroext %a, i16 zeroext %b)
-void f6(unsigned char a, unsigned short b) {}
-
-
-enum my_enum {
-  ENUM1,
-  ENUM2,
-  ENUM3,
-};
-// Enums should be treated as the underlying i32.
-// CHECK: define void @f7(i32 %a)
-void f7(enum my_enum a) {}
-
-enum my_big_enum {
-  ENUM4 = 0xFFFFFFFFFFFFFFFF,
-};
-// Big enums should be treated as the underlying i64.
-// CHECK: define void @f8(i64 %a)
-void f8(enum my_big_enum a) {}
-
-union simple_union {
-  int a;
-  char b;
-};
-// Unions should be passed as byval structs.
-// CHECK: define void @f9(%union.simple_union* byval align 4 %s)
-void f9(union simple_union s) {}
-
-typedef struct {
-  int b4 : 4;
-  int b3 : 3;
-  int b8 : 8;
-} bitfield1;
-// Bitfields should be passed as byval structs.
-// CHECK: define void @f10(%struct.bitfield1* byval align 4 %bf1)
-void f10(bitfield1 bf1) {}