fix the error "only proc headers can feature pragmas" when compiling in JS mode

lib/system.nim

@@ -447,6 +447,7 @@ proc chr*(u: range[0..255]): char {.magic: "Chr", noSideEffect.}
 # --------------------------------------------------------------------------
 # built-in operators
 
+when not defined(JS):
   proc ze*(x: int8): int {.magic: "Ze8ToI", noSideEffect.}
     ## zero extends a smaller integer type to ``int``. This treats `x` as
     ## unsigned.
@@ -479,7 +480,6 @@ proc toU32*(x: int64): int32 {.magic: "ToU32", noSideEffect.}
     ## treats `x` as unsigned and converts it to an ``int32`` by taking the
     ## last 32 bits from `x`.
 
-
 # integer calculations:
 proc `+` *(x: int): int {.magic: "UnaryPlusI", noSideEffect.}
 proc `+` *(x: int8): int8 {.magic: "UnaryPlusI", noSideEffect.}

lib/system/jssys.nim

@@ -472,17 +472,17 @@ proc Ze(a: int): int {.compilerproc.} =
 proc Ze64(a: int64): int64 {.compilerproc.} =
   result = a
 
-proc toU8(a: int): int8 {.noStackFrame, compilerproc.} =
+proc ToU8(a: int): int8 {.noStackFrame, compilerproc.} =
   asm """
     return `a`;
   """
 
-proc toU16(a: int): int16 {.noStackFrame, compilerproc.} =
+proc ToU16(a: int): int16 {.noStackFrame, compilerproc.} =
   asm """
     return `a`;
   """
 
-proc toU32(a: int): int32 {.noStackFrame, compilerproc.} =
+proc ToU32(a: int): int32 {.noStackFrame, compilerproc.} =
   asm """
     return `a`;
   """

tests/assert/tfailedassert.nim

@@ -3,7 +3,7 @@ discard """
 WARNING: false first asseertion from bar
 ERROR: false second assertion from bar
 -1
-tests/run/tfailedassert.nim:27 false assertion from foo
+tests/assert/tfailedassert.nim:27 false assertion from foo
 '''
 """