Bug 1499507 - Don't collect line numbers for profiling stack frames. r=njn

They were not displayed in the UI, and the instructions to initialize the line
field of a stack frame increased code size unnecessarily.

This change reduces the binary size on Linux x64 by around 100KB.

Here's a diff of the impact on the code generated for Attr_Binding::get_specified
in the Mac build:

@@ -20,17 +20,16 @@
    movq       0x8(%rbx), %rax
    movq       %r12, %rcx
    shlq       $0x5, %rcx
    leaq       aGetAttrspecifi, %rdx                       ; "get Attr.specified"
    movq       %rdx, (%rax,%rcx)
    movq       $0x0, 0x8(%rax,%rcx)
    leaq       -40(%rbp), %rdx
    movq       %rdx, 0x10(%rax,%rcx)
-   movl       $0x106, 0x18(%rax,%rcx)
    movl       $0x1c, 0x1c(%rax,%rcx)
    leal       0x1(%r12), %eax
    movl       %eax, 0x10(%rbx)

    movq       %r15, %rdi
    call       __ZNK7mozilla3dom4Attr9SpecifiedEv          ; mozilla::dom::Attr::Specified() const
    movzxl     %al, %eax
    movabsq    $0xfff9000000000000, %rcx

Depends on D9193

Differential Revision: https://phabricator.services.mozilla.com/D9195

dom/script/ScriptSettings.cpp

@@ -645,7 +645,7 @@ AutoEntryScript::AutoEntryScript(nsIGlobalObject* aGlobalObject,
   // ran.
   , mCallerOverride(cx())
 #ifdef MOZ_GECKO_PROFILER
-  , mAutoProfilerLabel("AutoEntryScript", aReason, __LINE__,
+  , mAutoProfilerLabel("AutoEntryScript", aReason,
                        js::ProfilingStackFrame::Category::JS)
 #endif
 {