glsl: Initialize ir_if_to_cond_assign_visitor members in constructor.

Fix defects reported by Coverity Scan.

Uninitialized scalar field (UNINIT_CTOR) uninit_member: Non-static class member found_unsupported_op is not initialized in this constructor nor in any functions that it calls. uninit_member: Non-static class member found_expensive_op is not initialized in this constructor nor in any functions that it calls. uninit_member: Non-static class member found_dynamic_arrayref is not initialized in this constructor nor in any functions that it calls. uninit_member: Non-static class member is_then is not initialized in this constructor nor in any functions that it calls. uninit_member: Non-static class member then_cost is not initialized in this constructor nor in any functions that it calls. uninit_member: Non-static class member else_cost is not initialized in this constructor nor in any functions that it calls.

Signed-off-by: Vinson Lee vlee@freedesktop.org