webkitgtk: turn off JIT on armv4 and armv7a

webkitgtk: turn off JIT on armv4 and armv7a

* It doesn't build on armv4:
{standard input}: Assembler messages:
{standard input}:52: Error: selected processor does not support `blx llint_throw_stack_overflow_error' in ARM mode
{standard input}:126: Error: selected processor does not support `bkpt #0' in ARM mode
{standard input}:128: Error: selected processor does not support `blx r0' in ARM mode
{standard input}:134: Error: selected processor does not support `bkpt #0' in ARM mode
{standard input}:185: Error: selected processor does not support `blx llint_throw_stack_overflow_error' in ARM mode
{standard input}:256: Error: selected processor does not support `blx r4' in ARM mode
{standard input}:310: Error: selected processor does not support `movw r2,#:lower16:.Lllint_op_enter-.LrelativePCBase' in ARM mode
{standard input}:311: Error: selected processor does not support `movt r2,#:upper16:.Lllint_op_enter-.LrelativePCBase' in ARM mode
{standard input}:315: Error: selected processor does not support `movw r2,#:lower16:.Lllint_op_get_scope-.LrelativePCBase' in ARM mode
{standard input}:316: Error: selected processor does not support `movt r2,#:upper16:.Lllint_op_get_scope-.LrelativePCBase' in ARM mode
[snip]

* It can build on armv7a, but doesn't work on runtime, cause
  displaying problems or ephiphany hang.

[YOCTO #9474]

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>