console: Add tests for calc_check_console_lines()

Add tests for checking:
- environment variable override with hex values
- invalid environment variable handling
- Kconfig-default behavior with device detection
- precedence rules (environment overrides device detection)
- serial terminal detection by manipulating sandbox state

Also expose calc_check_console_lines() in console.h for testing
and update pager functionality to use bypass mode when serial
is not connected to a terminal.

Co-Authored-By: Claude <noreply@anthropic.com>
Signed-off-by: Simon Glass <sjg@chromium.org>

test/common/Makefile

@@ -7,6 +7,7 @@ obj-$(CONFIG_$(PHASE_)CMDLINE) += bloblist.o
 endif
 endif
 
+obj-$(CONFIG_CONSOLE_PAGER) += console.o
 obj-$(CONFIG_CYCLIC) += cyclic.o
 obj-$(CONFIG_EVENT_DYNAMIC) += event.o
 obj-y += cread.o